Surveillance of environmental exposure and assessment of effects from pesticides to bat species in England.

Quantification of the exposure and effects of high impact pesticides in native bat species is required to allow conservation of protected species and represents essential novel national research of international standing. Presence of pesticides in bat species, including from within the UK and England have been identified.

However, the impacts of their toxicity have not been assessed. These facts are compounded by the fact that native bats are K-strategist species, are relatively long lived, have a high metabolic rate and therefore high nutritional intake requirements and undergo hibernation, all contributing to high risk from exposure to pesticides.

Insectivorous bats consume agricultural pests in large numbers and so have a high exposure rate to pesticides whilst fulfilling a value ecological service and benefit to agriculture. All these factors make bat species suitable as indicators of pesticide exposure and effects.

Pesticides will likely have an additive, synergistic or possibly antagonistic toxic effect upon exposed wildlife. It is essential to consider the toxic load of all relevant active substances together to determine risk to protected bat species.

Direct effects from exposure to pesticides in bats can be accessed via analysis of residues in bat carcasses and subsequent risk assessment. It is proposed that up to 50 bats are analysed annually for high-risk pesticides.

To elucidate effects of detected pesticides residues research will be required to allow determination of suitable toxicological thresholds for use to interrogate the exposure data. Only limited data exists in this area, comparison and adjustments will be required after considering all suitable international data available, including those from toxicological studies in other species such as mice.

The pesticide residue results from bat specimens will be reported with associated developed novel effect assessment methodology analysis to present a likely risk to these protected species. As this work will be of both national and international importance there is also the opportunity to present the data and outcomes via a paper published in international science literature. This work is designed to feed directly into the effects of chemicals on D4/D5 indicator species conducted by DEFRA Pressures.